Thermal relief valves are used in various applications which involve transporting fluid from a transmission to a heat exchanger in an automobile. In most applications, it is beneficial to have the fluid warm so that it can flow easier through tubes and components. In order to warm the fluid in a timely manner, a thermal relief valve is used to bypass the heat exchanger until an optimal operating temperature can be reached. Once this optimal temperature is reached, the thermal relief valve then allows the fluid to flow through the heat exchanger instead of bypassing it.
Available space in an engine bay and underneath an automobile can be limited, so it is important that any additional components such as a thermal relief valve take up as little space as possible. Additionally, the efficiency an automobile achieves is related to the weight of the car, so a thermal relief valve should also be as lightweight as possible while still acting as a bypass to the heat exchanger.
Since a thermal relief valve forces fluid to bypass a heat exchanger, the thermal relief valve must have a pressure release in order to prevent a blockage of the fluid. Since the fluid is responsible for the cooling of major components, such as the transmission, a blockage in the thermal relief valve would prevent any fluid from reaching the heat exchanger and would cause components to overheat while in operation causing extensive damage to the automobile.
A possible solution to this problem is disclosed in United States Patent Application Publication No. U.S. 2011/0061744 (Zillig et al.). Zillig et al. disclose a cooler bypass valve apparatus installed between a heat exchanger and conduits coupled to a device carrying fluid that needs to be cooled such as a radiator and transmission. A housing includes an inlet port and first and second outlet ports. At least one thermal actuator and at least one valve are mounted in a fluid flow passageway in the housing and actuate in response to the temperature of the fluid flowing within the apparatus. One valve that is arranged between an opened and closed position allows fluid to flow from the inlet port through the first and second outlet ports between a heat exchanger bypass loop and a heat exchanger cooling loop. In order to bypass the heat exchanger, sufficient pressure must be present within the system. Additionally, there are two thermal actuators which are arranged between the first and second outlets and actuate between opened and closed positions enabling fluid to only flow from the inlet port and through both the first and second outlet ports separately or in combination. Unfortunately, Zillig et al. fail to disclose an apparatus which bypasses the heat exchanger without any regard for the pressure within the system and also bypasses the heat exchanger completely instead of regulating the amount of fluid passing through the apparatus. Additionally, Zillig et al. fail to disclose an apparatus which includes a means for pressure relief which is axially arranged within the apparatus.
Another possible solution to this problem is disclosed in U.S. Pat. No. 8,141,790 (Sheppard). Sheppard discloses a bypass valve for a heat exchanger which allows fluid to flow through the heat exchanger at a certain operating temperature. A thermally sensitive actuator is mounted in the apparatus and can extend or retract depending on the temperature of the fluid flowing around the actuator. Once an optimal operating temperature has been reached, a bypass valve seat is arranged in a housing along with a bypass valve member which is movable by the actuator into an opened or closed position forcing the fluid to travel through the heat exchanger. A relief valve is mounted in the apparatus and has a relief valve member in order to close or open pressure relief ports. This relief valve member is biased towards the closed position to prevent excessive fluid from passing through the apparatus. Excessive pressure build up in the system would cause the relief valve member to move to an open position and allow fluid to flow through the apparatus. If the apparatus is not at an optimal operating temperature, the bypass valve member is not in a closed position which would allow fluid to flow freely through the apparatus without the need for the relief valve member. Unfortunately, Sheppard fails to disclose an apparatus which has the least amount of ports possible in order to save on weight and operating space. Additionally, Sheppard fails to disclose an apparatus which relieves the excessive pressure within the system while also guaranteeing fluid to flow through the heat exchanger and also fails to disclose a pressure relief means axially arranged within the apparatus.
Thus, there has been a long-felt need for a thermal relief valve that is both lightweight and compact while also comprising a pressure relief means axially arranged with a thermal relief means within the body of the apparatus.